1. Field of the Invention
The present invention relates to a high-frequency switching module for use primarily in a communications equipment and a high-frequency apparatus equipped with the same.
2. Description of the Prior Art
Conventionally, a multi-layer high-frequency switching module has a structure of a multi-layer assembly 1 formed of a dielectric material as shown in FIG. 10. The multi-layer assembly 1 has circuit electrodes (not shown) patterned therein and some high-frequency terminals 2 provided on sides thereof, and the high-frequency terminals 2 are connected to corresponding circuit electrodes and serve as input and output ports for high-frequency signals.
However, while a high-frequency apparatus such as a mobile telephone has significantly been minimized in overall size, a high-frequency switching module used therein is generally operated at such a high operating frequency as ranging from some hundreds MHz to some GHz, Therefore, in a structure of the high-frequency terminals 2 provided on the sides of the multi-layer assembly 1 designed as the input and output ports for high-frequency signals, the high-frequency terminals 2 act as an antenna and are highly susceptible to effects of the other neighbor components of higher density provided in the down-sized high-frequency apparatus.
Moreover, in a conventional electrode pattern construction in which high-frequency terminals are connected to circuit electrodes, there has been a problem that improvement in high-frequency characteristics of a high-frequency switching module is suppressed.
The present invention has been developed to solve these problems and has an essential object to provide a high-frequency switching module effectively avoiding the external effects and to provide a high-frequency apparatus equipped with the same.
Another object of the present invention is to provide a high-frequency switching module having improved high-frequency characteristics in which a transmission loss is reduced in the connecting construction between the high-frequency terminals and the circuit electrodes.
In order to achieve the objects mentioned above, the present invention provides a high-frequency switching module of a multi-layer assembly which is to be mounted on a circuit board of a high-frequency apparatus. In specific, high-frequency terminals are provided on a bottom surface of the multi-layer assembly where the bottom surface corresponds to a mounting side surface when mounted on a circuit board of a high-frequency apparatus while side surfaces of the multi-layer assembly are used as no-electrode provided sides.
The high-frequency switching module of the present invention is primarily includes a switching circuit and a filtering circuit, which comprises: a multi-layer assembly having a plurality of dielectric sheets of layers placed one over the other; and a plurality of high-frequency terminals provided on outer surfaces of the multi-layer assembly. The switching circuit is formed in the layers of the multi-layer assembly, having one end thereof connected to a first high-frequency terminal of the plurality of high-frequency terminals.
The filtering circuit is formed in the layers of the multi-layer assembly, having one end thereof connected to the other end of the switching circuit, and the other end connected to a second high-frequency terminal of the plurality of high-frequency terminals. In this construction, the high-frequency terminals are provided on a mounting side surface of the multi-layer assembly while lateral sides of the multi-layer assembly are not provided with any electrode for the high-frequency terminals.
By this arrangement, the high-frequency terminals acting as an antenna in a high frequency range are provided on the bottom side of the multi-layer assembly and the lateral sides thereof are not provided with any high-frequency terminal. Thus, the high-frequency terminals are hardly be affected by the effects of the other neighbor components.